Link Verification Configuration

In this section:

This section details best practices for configuring link detection groups.

Configuring link detection allows the SBC to switch over to a standby system based upon a configurable threshold of interface failures. Without link detection, the SBC does not use interface failures for SBC switchover determination.

Recommended threshold values (switchover criteria) are:

Port Type	Threshold
Management	2
Media	1

Ribbon recommends configuring only a single link monitor on any Ethernet port regardless of the number IP interfaces on that port.

Physical Link Detection

The user may configure a link monitor with a null destination (0.0.0.0) so that pinging is disabled so that only the physical health of the port is monitored. A null destination is normally recommended on external interfaces when the internal and external interfaces go to the same Ethernet switch pair.

Physical Link Detection is always instantaneous, regardless of Logical Link Detection.

Logical Link Detection

When a user configures a non-null destination for a link monitor, the link monitor periodically pings the destination (using ICMP Echo Request packets for the SBC 5000 series), and then retries if it fails to get a response. This technique is used to determine logical failures of the connected switch.

When configuring a SBC 5000 series link monitor with a non-null destination on any interface with a user-created Deny All ACL (Access Control List), ensure that there are earlier ACLs that allows ICMP responses from the link monitor destination IP addresses.

Most logical failures of a L3 switch, such as a route processor failure, do not cause its Ethernet ports to go down at the physical level (i.e. loss of carrier), thereby silently discarding traffic.

Ribbon recommends using a switch-local IP address for the destination, such as a Switch Virtual Interface (SVI, Cisco terminology) or a Routed VLAN Interface (RVI, Juniper terminology) rather than the VRRP/HSRP address. If such functionality is not available, the VRRP/HSRP/virtual-chassis IP address may be used as a link monitor destination.

Logical link detection should never be used as a peer checking mechanism (refer to Path Check Profile - CLI for that type of functionality).

Since the SBC 7000 uses ICMP on active port and ARP ACD probes on standby ports, the destination must be on the local subnet of the Media interfaces for SBC to perform probing.

The following timer and retry values are recommended:

Parameter	Value
verifyTimer	1000 ms
responseTimer	500 ms
reattemptTimer	1000 ms
retries	2

Logical link detection parameters (timers/retries) do not effect physical link failure detection (e.g. loss of carrier). Reaction to physical link failures are always instantaneous regardless of how logical link detection is configured.

Example Configurations

The diagram below depicts the generic recommended cabling configuration for the SBC 5000 series. The physical connections drive the link detection configuration.

Figure 1: SBC 5000 Series Cabling Configuration for Link Verification

Specifically, the above diagram shows the SBC 52x0 platform which has four media ports. The SBC 51x0 platform has only two media ports: MEDIA0 and MEDIA1. On the SBC 51x0, use MEDIA0 for External connectivity and MEDIA1 for Internal connectivity, if the default Ribbon convention is desired. MEDIA ports are not dedicated to Internal/External roles (i.e. roles can be reversed).

A second Ethernet switch pair (sw3 and sw4) is not required, but is shown for clarity (some deployments may have yet another separate switch pair for management ports).

Ribbon recommends that both management ports of each node connect to the same switch pair unless:

the user configures a link monitor null destination (0.0.0.0) on the management ports, or
the user has engaged Ribbon Professional Services to understand the pros and cons of deviating from that design.

The diagram below depicts the generic recommended cabling configuration for the SBC 7000. The physical connections drive the link detection configuration.

Table 2: SBC 7000 Series Cabling Configuration for Link Verification

Configuring Link Detection

The following example configuration applies to the SBC 5000 series.

set addressContext default linkDetectionGroup MANAGEMENT_LDG_A ceName SBC01A type mgmt linkMonitor LM_1 destination 10.1.1.2
set addressContext default linkDetectionGroup MANAGEMENT_LDG_A ceName SBC01A type mgmt linkMonitor LM_1 interfaceGroup mgmtGroup interface mgmtIntf1
set addressContext default linkDetectionGroup MANAGEMENT_LDG_A ceName SBC01A type mgmt linkMonitor LM_1 verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup MANAGEMENT_LDG_A ceName SBC01A type mgmt linkMonitor LM_1 state enabled

commit

set addressContext default linkDetectionGroup MANAGEMENT_LDG_A ceName SBC01A type mgmt linkMonitor LM_2 destination 10.1.1.2
set addressContext default linkDetectionGroup MANAGEMENT_LDG_A ceName SBC01A type mgmt linkMonitor LM_2 interfaceGroup mgmtGroup interface mgmtIntf2
set addressContext default linkDetectionGroup MANAGEMENT_LDG_A ceName SBC01A type mgmt linkMonitor LM_2 verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup MANAGEMENT_LDG_A ceName SBC01A type mgmt linkMonitor LM_2 state enabled

commit

set addressContext default linkDetectionGroup MANAGEMENT_LDG_B ceName SBC01B type mgmt linkMonitor LM_3 destination 10.1.1.3
set addressContext default linkDetectionGroup MANAGEMENT_LDG_B ceName SBC01B type mgmt linkMonitor LM_3 interfaceGroup mgmtGroup interface mgmtIntf3
set addressContext default linkDetectionGroup MANAGEMENT_LDG_B ceName SBC01B type mgmt linkMonitor LM_3 verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup MANAGEMENT_LDG_B ceName SBC01B type mgmt linkMonitor LM_3 state enabled

commit

set addressContext default linkDetectionGroup MANAGEMENT_LDG_B ceName SBC01B type mgmt linkMonitor LM_4 destination 10.1.1.3
set addressContext default linkDetectionGroup MANAGEMENT_LDG_B ceName SBC01B type mgmt linkMonitor LM_4 interfaceGroup mgmtGroup interface mgmtIntf4
set addressContext default linkDetectionGroup MANAGEMENT_LDG_B ceName SBC01B type mgmt linkMonitor LM_4 verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup MANAGEMENT_LDG_B ceName SBC01B type mgmt linkMonitor LM_4 state enabled

commit

set addressContext default linkDetectionGroup INTERNAL_LDG_A ceName SBC01A type ip linkMonitor LM_2A destination 10.2.2.2
set addressContext default linkDetectionGroup INTERNAL_LDG_A ceName SBC01A type ip linkMonitor LM_2A interfaceGroup INTERNAL_IPIG interface IPIF2_200
set addressContext default linkDetectionGroup INTERNAL_LDG_A ceName SBC01A type ip linkMonitor LM_2A verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup INTERNAL_LDG_A ceName SBC01A type ip linkMonitor LM_2A state enabled

commit

set addressContext default linkDetectionGroup INTERNAL_LDG_B ceName SBC01B type ip linkMonitor LM_2B destination 10.2.2.3
set addressContext default linkDetectionGroup INTERNAL_LDG_B ceName SBC01B type ip linkMonitor LM_2B interfaceGroup INTERNAL_IPIG interface IPIF2_200
set addressContext default linkDetectionGroup INTERNAL_LDG_B ceName SBC01B type ip linkMonitor LM_2B verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup INTERNAL_LDG_B ceName SBC01B type ip linkMonitor LM_2B state enabled

commit

set addressContext default linkDetectionGroup INTERNAL_LDG_A ceName SBC01A type ip linkMonitor LM_3A destination 10.2.2.2
set addressContext default linkDetectionGroup INTERNAL_LDG_A ceName SBC01A type ip linkMonitor LM_3A interfaceGroup INTERNAL_IPIG interface IPIF3_200
set addressContext default linkDetectionGroup INTERNAL_LDG_A ceName SBC01A type ip linkMonitor LM_3A verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup INTERNAL_LDG_A ceName SBC01A type ip linkMonitor LM_3A state enabled

commit

set addressContext default linkDetectionGroup INTERNAL_LDG_B ceName SBC01B type ip linkMonitor LM_3B destination 10.2.2.3
set addressContext default linkDetectionGroup INTERNAL_LDG_B ceName SBC01B type ip linkMonitor LM_3B interfaceGroup INTERNAL_IPIG interface IPIF3_200
set addressContext default linkDetectionGroup INTERNAL_LDG_B ceName SBC01B type ip linkMonitor LM_3B verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup INTERNAL_LDG_B ceName SBC01B type ip linkMonitor LM_3B state enabled

commit

set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_A ceName SBC01A type ip linkMonitor LM_0A destination 192.168.240.1
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_A ceName SBC01A type ip linkMonitor LM_0A interfaceGroup EXT_LD_IPIG interface IPIF0_300
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_A ceName SBC01A type ip linkMonitor LM_0A verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_A ceName SBC01A type ip linkMonitor LM_0A state enabled

commit

set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_B ceName SBC01B type ip linkMonitor LM_0B destination 192.168.240.2
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_B ceName SBC01B type ip linkMonitor LM_0B interfaceGroup EXT_LD_IPIG interface IPIF0_300
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_B ceName SBC01B type ip linkMonitor LM_0B verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_B ceName SBC01B type ip linkMonitor LM_0B state enabled

commit

set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_A ceName SBC01A type ip linkMonitor LM_1A destination 192.168.240.1
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_A ceName SBC01A type ip linkMonitor LM_1A interfaceGroup EXT_LD_IPIG interface IPIF1_300
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_A ceName SBC01A type ip linkMonitor LM_1A verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_A ceName SBC01A type ip linkMonitor LM_1A state enabled

commit

set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_B ceName SBC01B type ip linkMonitor LM_1B destination 192.168.240.2
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_B ceName SBC01B type ip linkMonitor LM_1B interfaceGroup EXT_LD_IPIG interface IPIF1_300
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_B ceName SBC01B type ip linkMonitor LM_1B verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_B ceName SBC01B type ip linkMonitor LM_1B state enabled

commit

set addressContext default linkDetectionGroup MANAGEMENT_LDG_A ceName SBC01A type mgmt threshold 2
set addressContext default linkDetectionGroup MANAGEMENT_LDG_A ceName SBC01A verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup MANAGEMENT_LDG_A ceName SBC01A state enabled

commit

set addressContext default linkDetectionGroup INTERNAL_LDG_A ceName SBC01A type ip threshold 1
set addressContext default linkDetectionGroup INTERNAL_LDG_A ceName SBC01A verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup INTERNAL_LDG_A ceName SBC01A state enabled

commit

set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_A ceName SBC01A type ip threshold 1
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_A ceName SBC01A verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_A ceName SBC01A state enabled

commit

set addressContext default linkDetectionGroup MANAGEMENT_LDG_B ceName SBC01B type mgmt threshold 2
set addressContext default linkDetectionGroup MANAGEMENT_LDG_B ceName SBC01B verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup MANAGEMENT_LDG_B ceName SBC01B state enabled

commit

set addressContext default linkDetectionGroup INTERNAL_LDG_B ceName SBC01B type ip threshold 1
set addressContext default linkDetectionGroup INTERNAL_LDG_B ceName SBC01B verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup INTERNAL_LDG_B ceName SBC01B state enabled

commit

set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_B ceName SBC01B type ip threshold 1
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_B ceName SBC01B verifyTimer 1000 responseTimer 500 reattemptTimer 1000 retries 2
set addressContext default linkDetectionGroup EXTERNAL_LD_LDG_B ceName SBC01B state enabled

commit

Configuring Physical Port

This applies to SBC 7000 only.

set addressContext ADDR_CONTEXT_1 linkDetectionGroup LDG1 ceName bf013.eng.sonusnet.com threshold 0 linkMonitor LM1 destination 10.7.6.50 interfaceGroup IFG_PKT0_0 interface LIF_PKT0_0 physicalPort pkt0_p state enabled
commit
set addressContext ADDR_CONTEXT_1 linkDetectionGroup LDG1 linkMonitor LM2 destination fd00:10:6b21:2007::6:50 interfaceGroup IFG_PKT0_0 interface LIF_PKT0_0 physicalPort pkt0_s state enabled
commit

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Physical Link Detection

Logical Link Detection

Example Configurations

Configuring Link Detection

Configuring Physical Port